Method and apparatus for using historic network information for determining approximate position

ABSTRACT

Systems and techniques to determine an approximate location for a mobile device using historic location information. In an aspect, a SUPL Location Platform (SLP), which is a location server in SUPL, may receive data from SUPL Enabled Terminal (SET). The data may include the Multiple Location IDs Parameter. The real time Location ID Parameter may not have a current status. The SLP may determine an approximate position for the SET based on the Multiple Location IDs Parameter data received from the SET. The SLP may then send the approximate position to the SET or a SUPL Agent, or may use the approximate position information in another way.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 60/885,338, filed on Jan. 17, 2007, which is hereby incorporated byreference in its entirety.

BACKGROUND

1. Field of the Invention

The present disclosure relates generally to communication, and morespecifically to techniques for supporting positioning.

2. Description of Related Art

Wireless communication networks are widely deployed to provide variouscommunication services, such as voice, video, packet data, messaging,broadcast, etc. These wireless networks may be multiple-access networkscapable of supporting communication for multiple users by sharing theavailable network resources. Examples of such multiple-access networksinclude Code Division Multiple Access (CDMA) networks, Time DivisionMultiple Access (TDMA) networks, Frequency Division Multiple Access(FDMA) networks, and Orthogonal FDMA (OFDMA) networks.

It is often desirable, and sometimes necessary, to know the location ofa terminal in a wireless network. The terms “location” and “position”are synonymous and are used interchangeably herein. For example, a usermay utilize the terminal to browse websites and may click on locationsensitive content. The location of the terminal may then be determinedand used to provide appropriate content to the user. There are manyother scenarios in which knowledge of the location of the terminal isuseful or necessary.

Various positioning methods may be used to determine the location of aterminal. Each positioning method may use certain information and mayrequire certain capabilities at the terminal and/or a location server inorder to compute a location estimate for the terminal. It is desirableto support positioning in an efficient manner in order to conserveresources and reduce delay.

SUMMARY

Techniques to support positioning for terminals are described herein.Positioning refers to a process to measure/compute a geographic locationestimate of a target device. A location estimate may also be referred toas a position estimate, a position fix, etc. Positioning may besupported with a location architecture/solution such as Secure UserPlane Location (SUPL) from Open Mobile Alliance (OMA).

In an aspect, a SUPL Location Platform (SLP), which is a location serverin SUPL, may receive data from SUPL Enabled Terminal (SET). The data mayinclude the Multiple Location IDs Parameter. The real time Location IDParameter may not have a “current” status. The SLP may determine anapproximate position for the SET based on the Multiple Location IDsParameter data received from the SET. The SLP may then send theapproximate position to the SET or a SUPL Agent, or may use theapproximate position information in another way.

Various aspects and features of the disclosure are described in furtherdetail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a deployment of different radio access networks.

FIG. 2 shows a message flow for network-initiated location services.

FIG. 3 shows a process performed by an SLP for positioning.

FIG. 4 shows a position grid of the historic locations of an SET.

FIG. 5 shows a position grid of the historic locations of an SET.

FIG. 6 shows a process that may be used for positioning.

DETAILED DESCRIPTION

As noted above, the ability to determine the location of a mobile devicecan be beneficial, or even necessary. A number of positioning techniquesare currently available. However, under some circumstances, obtaining alocation with sufficient accuracy can be challenging.

Some positioning techniques use an initial coarse position estimate toincrease the accuracy of the provided position, to reduce the time todetermining the provided position, or both. For example, in a satellitepositioning system such as GPS, the seed position allows the satelliteacquisition process to be performed more quickly, since the search spacecan be reduced. In some circumstances, the initial coarse positionestimate is needed to successfully determine a higher accuracy position.

Some techniques use the serving cell identity of a mobile station at thetime of the location request to provide a coarse position estimate.However, in some situations, the serving cell identity information isnot accurate, which can degrade positioning performance (e.g., increasethe amount of time needed to obtain a position fix). Systems andtechniques herein provide for more accurate and reliable positionestimates.

Techniques for supporting positioning in wireless networks are describedherein. The techniques may be used for various wireless networks such aswireless wide area networks (WWANs), wireless metropolitan area networks(WMANs), wireless local area networks (WLANs), broadcast networks, etc.The terms “network” and “system” are often used interchangeably.

A WWAN is a wireless network that provides communication coverage for alarge geographic area such as, e.g., a city, a state, or an entirecountry. A WWAN may be a cellular network such as a CDMA network, a TDMAnetwork, an FDMA network, an OFDMA network, etc. A CDMA network mayimplement a radio technology such as Wideband CDMA (WCDMA), cdma2000,Time Division-Synchronous Code Division Multiple Access (TD-SCDMA), etc.cdma2000 covers IS-2000, IS-95, and IS-856 standards. In the descriptionbelow, the term “CDMA” refers to cdma2000. A TDMA network may implementa radio technology such as Global System for Mobile Communications(GSM). An OFDMA network may implement a radio technology such as UltraMobile Broadband (UMB), Long Term Evolution (LTE), Flash-OFDM®, etc.These various radio technologies and standards are known in the art.WCDMA, GSM and LTE are described in documents from an organization named“3rd Generation Partnership Project” (3GPP). CDMA and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). 3GPP and 3GPP2 documents are publicly available.

A WLAN is a wireless network that provides communication coverage for asmall or medium geographic area such as, e.g., a building, a shop, amall, a home, etc. A WLAN may implement a radio technology such as anydefined by IEEE 802.11, Hiperlan, etc. A WMAN may implement a radiotechnology such as any defined by IEEE 802.16. IEEE 802.11 and 802.16are two families of standards from The Institute of Electrical andElectronics Engineers (IEEE). The IEEE 802.11 family includes 802.11a,802.11b, 802.11g and 802.11n standards and is commonly referred to asWi-Fi. The IEEE 802.16 family includes 802.16e and 802.16m standards andis commonly referred to as WiMAX.

FIG. 1 shows an example deployment of different radio access networks(RANs), which include a GSM network 110 a, a WCDMA network 110 b, a CDMAnetwork 110 c, and a WLAN 110 d. A radio access network supports radiocommunication for terminals and may be all or part of a WWAN, a WMAN, ora WLAN. For example, a WWAN may include a radio access network, a corenetwork, and/or other networks, and only the radio access networkportion is shown in FIG. 1 for simplicity. A radio access network mayalso be referred to as a radio network, an access network, etc. GSMnetwork 110 a, WCDMA network 110 b, and CDMA network 110 c may eachinclude any number of base stations that support radio communication forterminals within their coverage areas. A base station may also bereferred to as a Node B, an evolved Node B, etc. In GSM and WCDMAnetworks, the term “cell” can refer to the smallest coverage area of abase station and/or the base station subsystem serving this coveragearea. In CDMA networks, the term “sector” can refer to the smallestcoverage area of a base station and/or the base station subsystemserving this coverage area. WLAN 110 d may include any number of accesspoints (WLAN APs) that support radio communication for terminalsassociated with these access points.

A terminal such as SET 120 may communicate with GSM network 110 a, WCDMAnetwork 110 b, CDMA network 110 c, or WLAN 110 d at any given moment toobtain communication services. SET 120 may also simply receive signalsfrom these networks in order to make measurements or obtain informationuseful in computing its location. SET 120 may be stationary or mobileand may also be referred to as a mobile station, a user equipment, asubscriber station, a station, etc. A terminal may be a cellular phone,a personal digital assistant (PDA), a handheld device, a wirelessdevice, a laptop computer, a wireless modem, a cordless phone, atelemetry device, a tracking device, etc. Terminal 120 may also bereferred to as a SUPL Enabled Terminal (SET) in SUPL. The terms“terminal” and “SET” are used interchangeably herein.

SET 120 may receive and measure signals from satellites 190 to obtainpseudo-range measurements for the satellites. Satellites 190 may be partof the United States Global Positioning System (GPS), the EuropeanGalileo system, the Russian GLONASS system, or some other satellitepositioning system (SPS). SET 120 may also receive and measure signalsfrom access points in WLAN 110 d and/or signals from base stations inradio access networks 110 a, 110 b and/or 110 c to obtain timing and/orsignal strength measurements for the access points and/or base stations.SET 120 may communicate with one radio access network and may, at thesame time or an earlier time, receive and measure signals from accesspoints and/or base stations in other radio access networks to obtainmeasurements for these other access points and/or base stations. Themeasurements for satellites 190 and/or the measurements for the accesspoints and/or base stations may be used to determine the location of SET120.

Although aspects below are described using SUPL in an illustrativeexample, the use of historic network information is not limited toSecure User Plane Location (SUPL) systems.

A SUPL Location Platform (SLP) 130 may communicate with SET 120 tosupport location services and/or positioning for the SET. Thecommunication between SLP 130 and SET 120 may be via any one of radioaccess networks 110 a through 110 d and/or via other networks (e.g., theInternet). SLP 130 may be separate from radio access networks 110 a, 110b, 110 c and 110 d and may be from or part of a WWAN that includes radioaccess network 110 a, 110 b, 110 c and/or 110 d. SLP 130 may be a HomeSLP (H-SLP), a Visited SLP (V-SLP), or an Emergency SLP (E-SLP).

SLP 130 may support SUPL service management and positioning forterminals communicating with radio access networks 110 a through 110 d.SUPL service management may include managing locations of SETs andstoring, extracting, and modifying location information of target SETs.SLP 130 may include a SUPL Location Center (SLC) 132 and a SUPLPositioning Center (SPC) 134. SLC 132 may perform various functions forlocation services, coordinate the operation of SUPL, and interact withSETs. SLC 132 may perform functions for privacy, initiation, security,roaming support, charging/billing, service management, positioncalculation, etc. SPC 134 may support positioning for SETs and deliveryof assistance data to the SETs and may also be responsible for messagesand procedures used for position calculation. SPC 134 may performfunctions for security, assistance data delivery, reference retrieval,position calculation, etc. SPC 134 may have access to GPS receivers (areference network, perhaps a global one) and may receive signals forsatellites so that it can provide assistance data.

A SUPL agent 140 may communicate with SLP 130 to obtain locationinformation for SET 120. A SUPL agent is a service access point thataccesses network resources to obtain location information. Locationinformation may comprise a location estimate and/or any informationrelated to location. SET 120 may also have a SUPL agent that is residentwithin the SET. SET 120, SLP 130, and SUPL Agent 140 may each supportany SUPL version. SUPL Version 2.0 (SUPL 2.0) is described inOMA-AD-SUPL-V2, entitled “Secure User Plane Location Architecture,” Aug.31, 2007, and OMA-TS-ULP-V2, entitled “UserPlane Location Protocol,”Sep. 27, 2007. These SUPL documents are publicly available from OMA.

SET 120 may support one or more positioning methods, or measurements forone or more positioning methods, which may be used to determine thelocation of the SET. Table 1 lists some positioning methods that may besupported by SET 120 and provides a short description of eachpositioning method. Advanced Forward Link Trilateration (AFLT), EnhancedObserved Time Difference (E-OTD), and Observed Time Difference OfArrival (OTDOA) are positioning methods based on measurements for basestations in a radio access network, and may be referred to moregenerally as terrestrial range-based techniques. SET 120 may implementhybrid positioning techniques (combinations of different positioningtechniques, such as GPS and terrestrial ranging). In Table 1 as well asmuch of the description herein, “GPS” generically refers to positioningbased on any satellite positioning system, e.g., GPS, Galileo, GLONASS,etc.

TABLE 1 Positioning Method Description Cell-ID Location estimate isderived based on the identity (ID) of either a cell or WLAN AP servingarea in which a terminal is located. Accuracy is dependent on the sizeof the cell or AP serving area. Enhanced Location estimate is derivedbased Cell-ID on cell or AP ID and measurements for round trip delay(RTD), signal strength, etc. Information may be restricted to one cellor AP or may be provided for several cells and/or APs. In the lattercase, triangulation may be employed if multiple RTDs are available.AFLT, E-OTD, Location estimate is derived based on OTDOA timingmeasurements for base stations in a radio access network. AssistedLocation estimate is derived based on GPS satellite measurements withassistance from a network. Autonomous Location estimate is derived basedon GPS satellite measurements without assis- tance from any network.

SET 120 may be capable of communicating with different radio accessnetworks and/or may support different positioning methods. SLP 130 mayalso support different positioning methods and/or different radio accessnetworks, which may or may not match the positioning methods and radioaccess networks supported by SET 120.

In one design, the Location ID parameter may include any of theinformation shown in Table 2. The Cell Info parameter may include GSMcell information, WCDMA cell information, CDMA cell information, or WLANAP information. The Status parameter may indicate the status of thecell/AP information included in the Cell Info parameter.

TABLE 2 Location ID Parameter Parameter Presence Value/DescriptionLocation — Describes the globally unique cell or WLAN AP IDidentification of the most current serving cell or serving WLANAP. >Cell M The following cell IDs are supported: Info GSM Cell InfoWCDMA Cell Info CDMA Cell Info WLAN AP Info >Status M Describes whetheror not the cell or WLAN AP info is: Not Current, last known cell/AP infoCurrent, the present cell/AP info Unknown (i.e. not known whether thecell/AP id is current or not current) NOTE: The Status parameter doesnot apply to WCDMA optional parameters (Frequency Info, PrimaryScrambling Code and Measured Results List). Frequency Info, PrimaryScrambling Code and Measured Results List, if present, are alwaysconsidered to be correct for the current cell.

In one design, the Multiple Location IDs parameter may include any ofthe information shown in Table 3. The Multiple Location IDs parametermay include one or more Location ID parameters for one or more radioaccess networks, which may be obtained at the same time or differenttimes. The Multiple Location IDs parameter may be used, e.g., to reportWLAN measurements, cellular base station measurements, and otherposition related data for multiple access points and base stations nearSET 120 at both the current time and recent times in the past.

TABLE 3 Multiple Location IDs Parameter Parameter PresenceValue/Description Multiple — This parameter contains a set of upLocation to MaxLidSize Location ID/Relative ID Timestamp data. LocationM Describes measured globally unique ID cell/AP identification of theserving cell/AP or cell/AP identification from any receivable radionetwork. The measured cell/AP identifications may be from differentradio access networks measured at the same time or at different times.Relative CV Time stamp of measured location Id Timestamp relative to“current location id” in units of 0.01 sec. Range from 0 to 65535*0.01sec. Time stamp for current location Id if present is 0. The RelativeTimestamp is present if the Location ID info is historical and may beomitted if the Location ID info is current. Serving M This flagindicates whether the Cell Flag Location ID info represents a servingcell or WLAN AP or an idle (i.e., camped-on) cell or WLAN AP. If set,the Location ID info represents serving cell or WLAN AP information. Ifnot set, the Location ID info represents idle mode information orneighbor cell or WLAN AP information.

In one design, the WLAN AP information sent by SET 120 in the Cell Infoparameter of the Location ID parameter in Table 2 may include any of theinformation shown in Table 4.

Tables for various parameters in SUPL messages are given below. In atable for a given SUPL parameter, the first row of the table gives ashort description of the SUPL parameter. Subsequent rows give differentfields/parameters of the SUPL parameter, with each field being indicatedby symbol “>”. A given field/parameter may have subfields, with eachsubfield being indicated by symbol “>>”. A given subfield may havesub-subfields, with each sub-subfield being indicated by symbol “>>>”.

TABLE 4 WLAN AP Information Parameter Presence Value/Description WLAN APInfo — WLAN Access Point ID >AP MAC Address M Access Point MACAddress >AP Transmit Power O AP transmit power in dBm >AP Antenna Gain OAP antenna gain in dBi >AP S/N O AP S/N received at the SET indB >Device Type O Options are: 802.11a device, 802.11b device, and802.11g device. Future networks are permitted. >AP Signal Strength O APsignal strength received at the SET in dBm >AP Channel/ O APchannel/frequency of Tx/Rx Frequency >Round Trip Delay O Round tripdelay (RTD) between the SET and AP >>RTD Value M Measured RTDvalue >>RTD Units M Units for RTD value and RTD accuracy - 0.1, 1, 10,100 or 1000 nanoseconds >>RTD Accuracy O RTD standard deviation inrelative units >SET Transmit Power O SET transmit power in dBm >SETAntenna Gain O SET antenna gain in dBi >SET S/N O SET S/N received atthe AP in dB >SET Signal Strength O SET signal strength received at theAP in dBm >AP Reported O Location of the AP as reported by Location theAP >>Location Encoding M Location encoding description LCI as per RFC3825 Text as per RFC 4119 ASN.1 as per X.694 >>Location Data M LocationData >>>Location Accuracy O Location Accuracy in units of 0.1meter >>>Location Value M Location value in the format defined inLocation Encoding

In one design, the GSM cell information sent by SET 120 in the Cell Infoparameter of the Location ID parameter in Table 2 may include any of theinformation shown in Table 5.

TABLE 5 GSM Cell Information Parameter Presence Value/Description GsmCell — GSM Cell ID Info >MCC M Mobile Country Code, range: (0 . . .999) >MNC M Mobile Network Code, range: (0 . . . 999) >LAC M LocationArea Code, range: (0 . . . 65535) >CI M Cell Identity, range: (0 . . .65535) >NMR O Network Measurement Report - can be present for 1 to 15cells. >>ARFCN M ARFCN, range: (0 . . . 1023) >>BSIC M BSIC, range: (0 .. . 63) >>RXLev M RXLEV, range: (0 . . . 63) >TA O Timing Advance,range: (0 . . . 255)

In one design, the WCDMA cell information sent by SET 120 in the CellInfo parameter of the Location ID parameter in Table 2 may include anyof the information shown in Table 6.

TABLE 6 WCDMA Cell Information Parameter Presence Value/DescriptionWcdma/TD- — WCDMA Cell ID SCDMA Cell Info >MCC M Mobile Country Code,range: (0 . . . 999) >MNC M Mobile Network Code, range: (0 . . .999) >UC-ID M Cell Identity, range: (0 . . . 268435455). UC-ID iscomposed of RNC-ID and C-ID. >Frequency O Frequency info can be: Infofdd: uarfcn-UL, range: (0 . . . 16383) uarfcn-DL, range: (0 . . . 16383)In case of fdd, uarfcn-UL is optional while uarfcn-DL is mandatory. Ifuarfcn-UL is not present, the default duplex distance defined for theoper- ating frequency band shall be used [3GPP RRC]. tdd: uarfcn-Nt,range: (0 . . . 16383) NOTE: Frequency Info and Primary Scrambling Codeare always those of the current cell. >Primary O Primary ScramblingCode, range: Scrambling (0 . . . 511) Code >Measured O NetworkMeasurement Report for WCDMA Results comprising both intra- and/orinter- List frequency cell measurements (as per 3GPP TS 25.331).

In one design, the CDMA cell information sent by SET 120 in the CellInfo parameter of the Location ID parameter in Table 2 may include anyof the information shown in Table 7.

TABLE 7 CDMA Cell Information Parameter Presence Value/Description CdmaCell — CDMA Cell ID Info >NID CV Network ID, range: (0 . . . 65535) Thisparameter is conditional and only used for 1x in which case it ismandatory. >SID CV System ID, range: (0 . . . 32767) This parameter isconditional and only used for 1x in which case it is mandatory. >BASEIDCV Base Station ID, range: (0 . . . 65535) This parameter is conditionaland only used for 1x in which case it is mandatory. >SECTORID CV SectorID, length 128 bits This parameter is conditional and only used for HRPD(1xEV-DO) in which case it is mandatory. >BASELAT M Base StationLatitude, range: (0 . . . 4194303) >BASELONG M Base Station Longitude,range: (0 . . . 8388607) >REFPN CV Base Station PN Number, range: (0 . .. 511) This parameter is conditional and only used for 1x in which caseit is mandatory. >WeekNumber M GPS Week number, range: (0 . . .65535) >Seconds M GPS Seconds, range: (0 . . . 4194303)

Tables 4 through 7 show specific designs of WLAN AP information, GSMcell information, WCDMA cell information, and CDMA cell information. Ingeneral, the cell/AP information for a given radio access network maycomprise any information that may be used for positioning of a SET.

With the features in Tables 2 through 7, SET 120 may efficiently sendcell/AP information for different supported radio access networks to SLP130. In particular, SET 120 may send cell/AP information only for radioaccess networks and measurement parameters supported by SLP 130 and notfor radio access networks and measurement parameters not supported bySLP 130. This may reduce waste of radio and processing resources and mayalso reduce delay to send cell/AP information that SLP 130 cannot use.

FIG. 2 shows a design of a message flow 200 for network-initiatedlocation services in SUPL using supported network information. SUPLagent 140 may desire location information for SET 120 and may send aMobile Location Protocol (MLP) Standard Location Immediate Request(SLIR) message to SLP 130 (step A). Among the parameters specified inthe SLIR may be the expected quality of position (eqop). SLP 130 mayauthenticate and authorize SUPL agent 140 for the requested locationinformation. SLP 130 may then obtain routing information for SET 120(step B).

SLP 130 may send a SUPL INIT message to initiate a location session withSET 120 (step C). The SUPL INIT message may include a session-id used toidentify the location session, an intended positioning method(posmethod), the desired quality of positioning (QoP), supported networkinformation, etc. Upon receiving the SUPL INIT message, SET 120 mayperform a data connection setup procedure, attach itself to a packetdata network if the SET is not already attached, and establish a secureIP connection to SLP 130 (step D).

SET 120 may obtain cell or AP information for the radio access networkwith which SET 120 currently communicates and/or for other radio accessnetworks whose signals SET 120 currently receives or has received (stepE). In general, the cell/AP information may include any information forone or more base stations, access points, and/or terminals, which may bepertinent for positioning of a SET. SET 120 may send a SUPL POS INITmessage to SLP 130 (step F). The SUPL POS INIT message may include thesession-id, Location ID, SET capabilities, and Multiple Location IDs.Location ID and/or Multiple Location IDs may include network measurementinformation if reported by the SET. SLP 130 may determine a locationestimate for SET 120 based on the information contained in the LocationID (LID) received from the SET (step G). If the location estimateobtained from the information contained in the LID is of sufficientquality, then SLP 130 may send a SUPL END message to SET 120 (step 1)and may send the requested location information in an MLP StandardLocation Immediate Answer (SLIA) message to SUPL agent 140 (step J).

If a location estimate of sufficient quality is not obtained based onthe information contained in the LID received from SET 120, then SLP 130and SET 120 may exchange messages for a positioning session (step H).For SET-assisted positioning, SLP 130 may calculate a location estimatefor SET 120 based on positioning measurements received from the SET. ForSET-based positioning, SET 120 may calculate the location estimate basedon assistance from SLP 130. The location estimate, if any, obtained instep G may be used to assist step H (e.g., may be used to provideassistance data to SET 120 for positioning methods such as A-GPS) and/ormay be used to verify and improve any location estimate resulting fromstep H. In any case, upon completing the positioning session, SLP 130may send a SUPL END message to SET 120 (step I) and may also send therequested location information to SUPL agent 140 (step J).

If the Location ID received from the SET 120 (Step F) includes Cell Infowhose Status is Not Current or Unknown, the SLP 130 may not be able todetermine a location estimate for the SET 120. The SLP 130 may then notbe able to provide assistance data to the SET 120, which may be neededto support the positioning session of step H of FIG. 2. In somescenarios, the SLP 130 may then use a default location estimate thatencompasses a larger range. The quality of this position estimate maynot be sufficient to meet the expected quality of position requested bythe SUPL Agent 140, or may not be sufficient to provide adequateassistance data to the SET 120. In some cases, the process expected tobe completed using the Location ID Parameter information may abort.

As part of the information sent by the SET 120 to the SLP 130 in theSUPL POS INIT message, the SET 120 may have sent the Multiple LocationIDs parameter. As seen in Table 3, the Multiple Location IDs parameterpresents a history of prior Location IDs with time stamps associatedwith each entry. The Multiple Location IDs parameter data may allow forthe calculation of an approximated position for the SET 120 in the casewhere the cell/AP information in the Location ID parameter received fromthe SET 120 includes a Cell ID whose status is Not Current or Unknown.This approximated position for the SET 120 may then be used, instead ofthe use of a default position of lower quality, or instead of thetermination of operation due to lack of knowledge about presentposition. This approximated position for the SET 120 may be used togenerate assistance data needed to support a positioning session (stepH).

The historical location data as seen in the Multiple Location IDsparameter may allow for assessment of this location data and forcalculation of an approximated location for the SET 120 in circumstanceswhere the current location is not known. The approximated location mayalso have a quality of position associated based upon the assessment ofthe historical location data. For example, if the historical locationdata places the SET 120 in the same location, without discernablemotion, over the prior time periods, the SLP 130 may choose that samelocation as the approximated location of the SET 120 at that presentmoment. Alternately, if the historic location data shows a trend ofmotion over the stored time period, curve fitting and/or other trendingtechniques may be used to predict the present location, and thislocation may be used as the approximated location of the SET 120 at thepresent moment. In this context, the historic location data referred toabove may consist of cell/AP info, or other data, which may need to beprocessed to provide actual location.

As seen in Tables 4-7, data contained within the Multiple Location IDsparameter includes a variety of types of data. For each of thetimestamped Location ID parameters, there may be an Access Point ID orCell ID, depending upon the network type. There may also be other data,including measurement data, as seen in Tables 4-7. This other data isnot necessary to practice this invention in some aspects. This otherdata may be used in some aspects. However, what is used is the AccessPoint ID or Cell ID along with the time at which these IDs were current.

FIG. 3 shows a design of a process 300 performed by an SLP to supportpositioning in SUPL. Supported network information indicating one ormore radio access networks and/or measurement parameters supported bythe SLP may be sent to a terminal/SET (block 302). The supported networkinformation may indicate which measurement and/or which information maybe sent by the SET. In some aspects, the SET may send information to thenetwork without having received the supported network information.Network measurement information for at least one of the one or moreradio access networks supported by the SLP may be received from the SET(block 304). For a network-initiated SUPL session, the supported networkinformation may be sent in a SUPL INIT message, and the networkmeasurement information may be received in a SUPL POS INIT message,e.g., as shown in FIG. 2. For a SET-initiated SUPL session, thesupported network information may be sent in a SUPL RESPONSE message ora SUPL TRIGGERED RESPONSE message, and the network measurementinformation may be received in a SUPL POS INIT message.

The information included in the SUPL POS INIT message will include theLocation ID parameter, which has two components: Cell Info and Status(see Table 2). The SLP assesses the Location ID data (block 306). If theLocation ID Cell Info Status is Current, the SLP may proceed todetermine the location estimate for the SET (308). If the Location IDCell Info Status is other than Current (Not Current or Unknown), the SLPmay assess the Multiple Location IDs parameter date (block 310). Thehistoric location data may be used to determine the approximate positionof the SET (block 312). The process 300 may be used in either a SET ornetwork initiated scenario.

FIG. 4 illustrates a graphical representation of historic location data.The grid 400 may be broken into blocks 401 which represent location. Theblocks may be indicative of a latitude and longitude combination.Although shown here with equal size blocks, the grid may have blocks ofdifferent sizes, depending upon the type and quality of data relating tothe historic locations. The numbers seen in the grid may representlocations of the SET at earlier time periods, with the lower numbersbeing further back in time. In this example, the historic locations arelocated close to each other, and a curve fitting program, or othermethod of extrapolating position, may select a present approximateposition 402. FIG. 5 illustrates a graphical representation of anotherset of historical location data placed in a grid 500 made up of locationblocks 501. The blocks may be indicative of a latitude and longitudecombination. The data indicates general motion over time, leading to theselection of an approximate position 502 expected based upon analysis ofthe data.

As seen in FIG. 3, the Multiple Location ID parameter may contain manyLocation ID/timestamp entries. With each of the past timestampedLocation ID parameters, there may be a Cell Info parameter which iseither Current, Not Current, or Unknown. In one design, only priorLocation ID parameters wherein the Cell Info is Current will be used inthe assessment of the prior location data to determine a currentposition.

Different Location ID/timestamp entries may have different associateduncertainties with regard to the accuracy of the location. For example,some historic locations may have higher accuracy than others. Curvefitting or trending solutions may take the variable accuracy of the datainto account.

Depending upon the coherence of the historic location data relative totime, the expected accuracy of the calculated approximated position mayalso be assessed using standard methods. For example, if the historiclocation data is grouped in an orderly manner relative to its timestamp, the deviation of the data from the curve fit to that data may besmall, and thus the accuracy may be high. The expected accuracy of thecalculated approximated position may depend upon the uncertaintyassociated with each individual past location data point, as well as thegrouping of the past location data points. Thus, a calculatedapproximate position may or may not be found to be within the expectedquality of position as requested by a SUPL Agent, or as needed inanother operation.

FIG. 6 shows a process 600 that may be used to determine a position of amobile device such as terminal 120 of FIG. 1. At 610, a determination ismade that the current location parameter identification information isnot sufficiently reliable. Referring to the implementations describedabove, this may correspond to a determination that the cell ID or accesspoint ID has a status different from “Current” (e.g., “Unknown” or “NotCurrent”).

At 620, historic location parameter identification information isaccessed, based on the determination that the current information is notsufficiently reliable. For example, historic time-stamped cell IDinformation or access point ID information is accessed.

At 630, the historic location parameter identification information isprocessed, and an output of the processing is provided. For example, thetime-stamped cell ID or access point ID information may be processedusing curve-fitting, interpolation, or other trending analysistechniques.

At 640, information indicative of an approximate position of the mobiledevice is determined using the output of the processing of the historiclocation parameter identification information. For example, theprocessing may indicate that the mobile device is stationary (or closeto stationary), and the output of the processing may be the cell ID oraccess point ID that had a status of “Unknown” or “Not Current.” Inanother example, curve fitting or other trending techniques maydetermine that the mobile device was moving in a particular direction ortrajectory, and a different cell ID, access point ID, or position may beprovided based on the trend. Note that output of the processing may bedifferent than the kind of information used as an input to theprocessing. For example, the input may be a cell ID corresponding to acell associated with a particular position (such as the cell center).However, the output may correspond to a position that is not anothercell ID, but rather a position offset from the previous cell ID by aparticular amount (determined by the trending analysis). Of course, manyimplementations are possible.

At 650, the information indicative of the approximate position may beused to determine a provided location for the mobile device. Forexample, the approximate position information may be used as seedposition information for a satellite positioning fix.

The apparatus used to implement the above techniques may include anumber of features. For example, a mobile device such as terminal 120 ofFIG. 1 may include memory and processor modules to implement the abovetechniques. For example, the mobile device may be configured to storehistoric location parameter identification information. The historiclocation parameter identification information may be associated withtime information, as noted above. The historic location parameteridentification information can include (for example) serving cellidentities with associated status indication, channel information suchas frequency, code, and/or timing, received signal strength or servicequality and neighboring cell measurements. In one example, the mobiledevice may store at least time-stamped cell ID and/or access point IDinformation. The mobile device may also include hardware, software,firmware, or a combination to implement techniques described above. Forexample, for a SUPL implementation, the mobile device may be configuredto format and transmit historic location parameter identificationinformation in the form of the Multiple Location ID parameter.

Similarly, a network device or devices can use the historic locationparameter identification information to provide more accurateapproximate position information for the mobile device. For example, anetwork system such as SUPL SLP 130 (which may include one or moreservers) may receive historic location parameter identificationinformation and determine more accurate approximate position informationtherefrom. As noted above, one or more trending techniques may be used.

For a firmware and/or software implementation, the techniques may beimplemented with code (e.g., procedures, functions, modules,instructions, etc.) that performs the functions described herein. Ingeneral, any computer/processor-readable medium tangibly embodyingfirmware and/or software code may be used in implementing the techniquesdescribed herein. For example, the firmware and/or software code may bestored in a memory and executed by a processor. The memory may beimplemented within the processor or external to the processor. Thefirmware and/or software code may also be stored in acomputer/processor-readable medium such as random access memory (RAM),read-only memory (ROM), non-volatile random access memory (NVRAM),programmable read-only memory (PROM), electrically erasable PROM(EEPROM), FLASH memory, floppy disk, compact disc (CD), digitalversatile disc (DVD), magnetic or optical data storage device, etc. Thecode may be executable by one or more computers/processors and may causethe computer/processor(s) to perform certain aspects of thefunctionality described herein.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

1. A method for determining the position of a mobile device, said methodcomprising: in a mobile device, storing historic location informationand associated time information; transmitting current locationinformation and at least some historic location information from themobile device to a network; and receiving from the network approximatelocation information based on the at least some historic locationinformation; and using the approximate location information to determinethe current position of the mobile device.
 2. The method of claim 1wherein said historic location information includes past location datapaired with time stamp data for said past location data.
 3. The methodof claim 2 wherein said past location data comprises a cell ID.
 4. Themethod of claim 2 wherein said past location data comprises an accesspoint ID.
 5. The method of claim 2 further comprising curve fitting thepast location data with the time stamp data to determine the currentposition of the mobile device.
 6. A method for determining the positionof a mobile device, said method comprising: in a network, receivingcurrent location information and at least some historic locationinformation from a mobile device; using the historic locationinformation to determine approximated current location information; andusing the approximate location information to determine the currentposition of the mobile device.
 7. The method of claim 6 wherein saidhistoric location information includes past location data paired withtime stamp data for said past location data.
 8. The method of claim 7wherein said past location data comprises a cell ID.
 9. The method ofclaim 7 wherein said past location data comprises an access point ID.10. The method of claim 7 further comprising curve fitting the pastlocation data with the time stamp data to determine the current positionof the mobile device.
 11. An apparatus for supporting positioningcomprising: a processor, said processor adapted to: receive historiclocation data from a mobile device and determine a location estimate forthe mobile device based on the historic location data; and a memorycoupled to the processor.
 12. The apparatus of claim 11, wherein theprocessor is further adapted to determine a current position of themobile device based on the location estimate.
 13. The apparatus of claim11 wherein the processor is adapted to send the location estimate to themobile device.
 14. The apparatus of claim 13 further comprising a mobiledevice, and wherein the mobile device is configured to determine acurrent position of the mobile device based on the location estimate.15. A method of supporting positioning in Secure User Plane Location(SUPL), comprising: obtaining historic network information for at leastone of the one or more radio access networks supported by the SUPLLocation Platform (SULP); and sending the historic network informationfrom a SUPL Enabled Terminal (SET) to the SULP.
 16. The method of claim15 further comprising: receiving supported network information from aSUPL Location Platform (SLP), wherein the supported network informationindicates whether a SUPL Enabled Terminal (SET) is allowed to sendhistoric network information; determining one or more radio accessnetworks supported by the SLP based on the supported networkinformation;
 17. The method of claim 16 further comprising determining alocation estimate for the SET based on the historic network information.18. The method of claim 17 wherein the determining a location estimatefor the SET based on the historic network measurement informationcomprises determining a location estimate based upon historic locationinformation.
 19. The method of claim 18 wherein said historic locationinformation comprises a Multiple Location IDs parameter.
 20. The methodof claim 19 further comprising estimating an accuracy of the locationestimate for the SET.
 21. The method of claim 19 further comprisingpreparing assistance data based upon the location estimate for the SET.22. The method of claim 21 further comprising sending said assistancedata from the SLP to the SET.
 23. A method of supporting positioning inSecure User Plane Location (SUPL), comprising: receiving supportednetwork information from a SUPL Location Platform (SULP), wherein thesupported network information indicates whether a SUPL Enabled Terminal(SET) is allowed to send current and historic network measurementinformation; determining one or more radio access networks supported bythe SLP based on the supported network information, obtaining presenttime and historic network information for at least one of the one ormore radio access networks supported by the SLP; and sending the presenttime and historic network information from a SET to the SULP.
 24. Themethod of claim 23 wherein said current network information comprisesthe Location ID parameter.
 25. The method of claim 24 further comprisingassessing whether the Status component of the Location ID is Current.26. The method of claim 25 further comprising determining a locationestimate for the SET based on the historic network information.
 27. Themethod of claim 26 wherein the determining a location estimate for theSET based on the historic network information comprises determining alocation estimate based upon historic location information.
 28. Themethod of claim 27 wherein said historic location information comprisesa Multiple Location IDs parameter.
 29. The method of claim 28 whereinsaid Multiple Location IDs parameter comprises a cell ID.
 30. Anapparatus for supporting positioning in Secure User Plane Location(SUPL), comprising: a processor adapted to send from a SUPL LocationPlatform (SLP) to a SUPL Enabled Terminal (SET) supported networkinformation indicating one or more radio access networks supported bythe SLP, and adapted to receive from the SET network information for atleast one of the one or more radio access networks supported by the SLP,wherein said network information comprises historic location data; and amemory coupled to the processor.
 31. The apparatus of claim 30, whereinthe processor is adapted to determine a location estimate for the SETbased on the historic location data.
 32. The apparatus of claim 31wherein the processor is adapted to send the location estimate to theSET or a SUPL Agent.
 33. A computer program product, comprising:computer-readable medium having instructions stored thereon to cause oneor more machines to perform operations comprising: determining whetherthere is current estimated location information for a mobile device; ifthere is not current estimated location information for the mobiledevice, accessing historic location information; and determining anestimated location of the mobile device using the historic locationinformation.
 34. The computer program product of claim 33 wherein saidoperations further comprise: determining the location of the mobiledevice using the estimated location of the mobile device.
 35. Thecomputer program product of claim 33 wherein said operations furthercomprise: generating assistance data to be sent to the mobile devicebased upon the estimated location of the mobile device.
 36. An apparatusfor determining the position of a mobile device comprising: means forreceiving current location information and at least some historiclocation information from a mobile device; means for using the historiclocation information to determine approximated current locationinformation; and means for using the approximate location information todetermine the current position of the mobile device.
 37. The apparatusof claim 36 wherein said historic location information includes pastlocation data paired with time stamp data for said past location data.38. The apparatus of claim 37 wherein said past location data comprisesa cell ID.
 39. The apparatus of claim 37 wherein said past location datacomprises an access point ID.
 40. The apparatus of claim 38 furthercomprising the mobile device.
 41. An apparatus for determining theposition of a mobile device, said apparatus comprising: in a mobiledevice, means for storing historic location information and associatedtime information; means for transmitting current location informationand at least some historic location information from the mobile deviceto a network; means for receiving from the network approximate locationinformation based on the at least some historic location information;and means for using the approximate location information to determine acurrent position of the mobile device.
 42. The apparatus of claim 41wherein said historic location information includes past location datapaired with time stamp data for said past location data.
 43. Theapparatus of claim 42 wherein said past location data comprises a cellID.
 44. The apparatus of claim 42 wherein said past location datacomprises an access point ID.
 45. The apparatus of claim 42 furthercomprising the step of curve fitting the past location data with thetime stamp data to determine the current position of the mobile device.